Clamshell

Clamshell (pronounced klam-shel)

(1) The shell of a clam.

(2) Any of a variety of object with two hinged parts and that opens and closes like a clamshell, as a laptop computer or a box with a cover joined on one side (clamshell phone; clamshell computer, clamshell packaging etc).

(3) In dredging and earth-moving machinery, a dredging bucket opening at the bottom, consisting of two similar pieces hinged together at the top (also called the clamshell bucket); a machine equipped with such a bucket.

(4) In printing, a platen press.

(5) Of, pertaining to or noting an object that opens and closes like a clamshell; the opening and closing actions of this object (ie anything resembling the bivalve shell of a clam).

(6) In anatomy, another name for eyelid (technical use only).

(7) In aviation, (1) an aircraft cockpit canopy hinged at the front and rear or (2) the hinged door of a cargo aircraft.

(8) In slang, the mouth (US archaic).

(9) In architecture, an amphitheater, especially an outdoor amphitheater; the semi-circular acoustic backdrop behind and above the performers (a use based (unusually) on the appearance of the shell in only its open state).

(10) In manufacturing, to deform a die in a shape resembling the shell of a clam, as a result of uneven extrusion pressure.

1490–1500: the construct was clam + shell.  Clam was from the Middle English clam (pincers, vice, clamp), from the Old English clamm (bond, fetter, grip, grasp), from the Proto-Germanic klamjaną (press, squeeze together).  Shell was from the Middle English schelle, from the Old English sċiell, from the Proto-West Germanic skallju, from the Proto-Germanic skaljō, from the primitive Indo-European skelh & kelh (to split, cleave).  It was related to the West Frisian skyl (peel, rind), the Dutch schil (peel, skin, rink), the Low German Schell (shell, scale), the Irish scelec (pebble), the Latin silex (pebble, flint) & siliqua (pod) and the Old Church Slavonic сколика (skolika) (shell).  Although sharing a source, the adjective clammy is otherwise unrelated, being from the Middle English clam (in the literally descriptive sense of “viscous, sticky, slimy”) & clammen (“to smear, bedaub”), from the Old English clǣman (to smear, bedaub) and related to the German klamm (clammy) & klemmen (to be stuck, stick).  Clamshell is a noun, the present participle is clamshelling and the past participle clamshelled; the noun plural is clamshells.

Lindsay Lohan with T-Mobile flip-phone Sidekick II, T-Mobile Sidekick II party, The Grove, Los Angeles, August 2004.

In (mostly archaic) US slang, a clam was one dollar (used usually in the plural) and it’s though the origin of this was an allusion to the wampum (a traditional shell bead of the Eastern Woodlands tribes of Native Americans.  It includes white shell beads hand-fashioned from the North Atlantic channeled whelk shell and white and purple beads made from the quahog or Western North Atlantic hard-shelled clam.).  Clams are of some note in the strange history of the Church of Scientology, a tax-exempt operation created by L Ron Hubbard (1911–1986) who constructed its ethos from an amalgam of his science fiction and fantasy stories, combined with pseudo-scientific explanations about the human condition.  His idea (a central tenet of Scientology) that human “thetans” (souls) previously inhabited clams he expanded upon in Scientology: A History of Man (1961) (first published as What to Audit (1952)), explaining that interactions between jellyfish and cave walls were responsible for the emergence of “a shell as in the clam” and that the clam itself suffered from a split personality when he described as a “double-hinge problem” in which “…one hinge wishes to stay open, the other tries to close, thus conflict occurs".  That does of course explain much about the problems of man and, more prosaically, because the clam’s hinges would become the Clam “hinges of the human jaw”, the Clam's method of issuing spores to reproduce is why we suffer toothache.  Who knew?

Trendsetter: The influential clamshell and some of its many imitators.

What engineers and designers liked once to call the “clam shell form factor” was shortened inevitability to “clamshell” but for portable computers and cellular (mobile) phones neither term caught on, laptop soon the ubiquitous choice and phone users preferred the punchier flip-phone.  Laptop endured as the generic description of all such devices and the distinction manufacturers applied to models technically classed as notebooks and netbooks escaped most, any clamshell computer since first they appeared in the early 1980s most often referred to as a laptop.  The flip-phone was a turn of the century fad and actually a good example of packaging efficiency, especially for those who carried their phones in handbags although men, most of whom had only pockets, were never as enthusiastic.  As it was the sleek iPhone and the smartphones which followed in its wake killed off most flips although there was the occasional retro-themed revival.  However, advances in materials had by 2020 made folding screens both durable and economical to produce in volume so these have become the latest variation to use the clam shell, offering all the packaging advantages of old with the benefit of being able to offer a flip screen in a thin form factor, thus appealing also to men, few of whom have been convinced by the utility of that other turn of the century fad: the man bag.

1983 Ferrari 512BBi.  All versions of the BB (1973-1984) used the clamshell design front & rear.

In automotive design, clamshells are used for both front and rear sections of the bodywork, some cars using both.  It was a popular idea on racing machinery like the Ford GT40 or the Porsche 917 because the method of construction used meant the panels carried little load, providing just coverage and aerodynamic optimization.  Some road cars also adopted the idea including Triumph’s Spitfire (and the GT6 derivative) and Jaguar’s E-Type (XK-E) and there were real advantages in accessibility for servicing and that’s probably why the bulky Jaguar V12 enjoyed a better reputation among mechanics when under the clamshell than it did in the tighter confines of the XJ or XJ-S.  Few mass-market vehicles used the idea and the Triumph Herald and Vitesse (which provided the platforms for the Spitfire & GT6) was one of the few but it was unusual in being built on a separate chassis after most of the industry had switched to unitary construction.